Method of close coiling sheathed spring wire



J. E. DUFF METHOD OF CLOSE COILING SHEATHED SPRI NG WIRE Filed March 18, 1955 2 sheets-shut 1 w riu l I J. E. DUFF METHOD OF CLOSE COILING SHEATHED SPRING WIRE Filed March 18, 1955,

2 Sheets-Sheet 2 United States Patent-015cc 2,793,672 Patented May28, 1957 METHOD OF CLOSE COILING SHEATHED SPRING WIRE Jack E. Dulf, Canton, Ohio, assignor to The Hoover Company, North Canton, Ohio, a corporation of Ohio Application March 18, 1955, Serial No. 495,159

2 Claims. (Cl. 153-65) The present invention relates to a machine and method of close coiling a spring wire which has been previously sheathed in a thermoplastic covering preparatory to the formation of a flexible hose of the type disclosed and claimed in my copending application, Serial No. 415,256, filed March 10, 1954, now U. S. Patent No. 2,739,616, dated March 27, 1956.

The usual wire coiler coils an uncoated spring wire with the turns spaced apart at a definite pitch and feeds the wire against a fixed abutment in the formation of the turns of the coil.

A special problem is involved in coiling a thermoplastically coated spring wire. Usually, the thermoplastic coating is unbonded to the wire, and it would be im possible to coil such a wire with the prior wire coiling machines in which the wire is moved across a fixed element because the thermoplastic coating would be displaced lengthwise of the wire and possibly stripped from the wire to form bare spots on the wire or bulges in the thermoplastic sheath. As a result, every element of the coiling machine which comes into contact with the sheathed wire must be movable, and the peripheral speed of each such part must be the same, for otherwise the sheath would be displaced lengthwise of the wire resulting in a defective reinforcing helix.

, Another problem involved is close coiling the spring so that its turns normally press against each other. The grooves of the coiling rolls must be in substantial alignment and adjustable so as to vary the pressure which the turns of the coil exert against each other and in order to control the diameter of the helix.

According to the present invention, all of the parts of the wire coiler are rotatable or movable and so geared together that their peripheral speed is the same, and that includes the advancing rolls which advance the coated wire from a reel upon which it is stored.

The machine of the present invention may form an indefinite length of coiled sheathed Wire which is projected onto a conveyor comprising spaced apart rolls rotating in the same direction and eo-ordinated with the coil forming rolls so that the peripheral speed of the coiled wire will be the same as its peripheral speed as it comes from the forming rolls. The rotating conveyor rolls are for the purpose of preventing the turns of the coils from kinking as the coil moves from the forming rolls.

However, since definite lengths of coiled spring are needed in the manufacture of hose, a sort of counting mechanism is provided, and the wire severed when the required number of turns have been formed. The severed length of closely coiled sheathed wire may then be removed from the conveyor and stored for future use in the manufacture of an extensible hose as described in my above-mentioned copending application.

Other objects and advantages of the present invention will become apparent as the description proceeds when taken in connection with the accompanying drawings in which:

Figure 1 is a schematic view of the general arrangement of the machine of the present invention,

Figure 2 is a side plan view of the conveyor for receiving the coiled reinforcing element, and

Figure 3 is a detailed view of the coiling mechanism of the present invention taken on line 3-3 of Figure 1 showing how the coil is formed.

The reinforcing element 4 (Figure 3) to be formed by the machine and method of the present invention comprises a steel spring wire 5 encased in a sheath 6 of thermoplastic material so wound that its turns 7 press against each other The sheath 6 may be extruded about the Wire 5 in a manner well known in the art, and the sheathed wire wound about a storage reel 8 as shown in Figure 1.

Referring to Figure 1 of the drawings, the reference numeral 10 generally represents the frame work of the coiling mechanism of thepresent invention. The frame work 10 includes the casing 11 in which a driving motor and gearing (not shown) for driving the various forming and advancing rolls is housed.

Attached to the housing 11 is a cantilever type bracket which supports two sets of straightening rolls 12 and 13. The rolls 12 straighten the reinforcing element 4 in a vertical direction while the rolls 13 straighten it in a horizontal direction with the result that any kinks in the reinforcing element are removed before it passes through the coiling machine.

The reference numerals 14, 15, 16 and 17 represent advancing rolls which pull the reinforcing element 4 from the reel 8 through the straightening rolls 12 and 13 to a coiling station generally indicated by the reference numeral 20.

At the forming station 20, the reinforcing element 4 is advanced between a pair of forming rolls 21 and 22, and it is to be noted that the reinforcing element 4 enters between the rolls 21 and 22 at a point of less radius than that of the turns 7 of the completed coil. As shown, the forming rolls are grooved at 23 and 24 to have a maximum peripheral frictional contact with the reinforcing element 4.

From the forming rolls 21 and 22, the reinforcing element 4 is advanced through forming and advancing rolls 25 and 26 which are grooved to fit the periphery of the reinforcing element 4. The turns 7 of the coil are advanced between the advancing roll 26 and a guide shoe 27 in order to smooth out the turns of the coil. An adjustment 28 is provided whereby the pressure applied to the turns 7 of the coil by the forming and advancing roll 26 may be varied so as to control the finished diameter of the turns.

There are two essential characteristics of the machine as so far described.

Firstly, the peripheral speed of the advancing rolls 14, 15, 16 and 17 must be the same as the peripheral speed of the forming and advancing rolls 21, 22, 25 and 26. Qtherwise, the sheath 6 would be stripped from the wire 5. Suitable gearing, within the skill of the art, is provided within the casing 11 for that purpose.

Secondly, the grooves of the forming and advancing rolls 21, 22, 25 and 26 must be so related that the turns 7 of the coil will be prestressed so as to press against each other. It has been found in practice that that may be accomplished by mounting the rolls 21, 22, 25 and 26 so that their grooves are in a common plane with the result that the turns 7 of the reinforcing element 4 are constrained to take a position in contact with each other.

As the tightly Wound coil 7 leaves the forming station 20, it is rotating and means are provided to regulate that rotation so that the coil will not become distorted after it leaves the forming station 20. A take off station generally indicated by the reference numeral 30 is provided for that purpose.

The take off conveyor 30 comprises two rolls 31 and 32 which rotate in the same direction as indicated by the arrows in Figure 1 so that the coiled reinforcing element 4 is rotated in the same direction as it is rotating as it leaves the forming station 20, which is in the direction indicated by the arrow of Figure l.

The take off rolls 31 and 32 are inclined downwardly from the forming station 20 and are supported by standards 33 and 34 which support a rod 35 having end bearings 36 and 37 upon which the rolls 31 and 32 are rotatably mounted.

The roll 32 is positively rotated by a belt 40 which encircles a pulley on one end of the advancing roll 15 and also the end of the roll 32. A belt 41 encircles the other end of roll 32 and the lower end of roll 31 so that the two rolls are rotated in unison at the same speed and in the same direction.

The belt gearing 40 is so designed with relation to the advancing rolls 15, etc., that the speed of rotation of the rolls 31 and 32 will be the same as the rotative speed of the coil 4 as it leaves the forming station 20 so that kinks will not be formed in the coil 4, and its sheath 6 will not be displaced relative to the wire 5.

The above unison of motion of the various moving parts of the machine are especially important because the sheath 6 is not bonded to the wire 5, and any variation in the peripheral speed of the various moving parts would displace the sheath 6 relative to the wire and result in a defective coil.

It is also to be noted that all of the advancing and forming parts are movable at the same peripheral speed to the same end, that is, that no forces will be applied to the sheath 6 tending to move it longitudinally of the wire 5.

The guide and advancing rolls are grooved to fit the periphery 6 of the reinforcing element and are in frictional engagement therewith so that the reinforcing element 4 is smoothly advanced through the machine. At no point is there any tendency for the sheath to be displaced relative to the wire because all coil forming forces are applied perpendicular to the axis of the wire. While the guide 27 is stationary, it cooperates with the roll 26 to fix the diameter of the coil 4 and does not displace the sheath relative to the wire.

From the foregoing description, it can be seen that the present invention provides a coiling machine especially designed for close coiling a sheathed reinforcing element in which there is no tendency to displace the sheath lengthwise of the wire since all the parts move in unison at the proper peripheral speed.

While I have shown and described but a single embodiment of my invention, it is to be understood that that embodiment is to be taken as illustrative only and not in a limiting sense. I do not wish to be limited to the particular structure shown and described, but wish to include all equivalent variations thereof except as limited by the scope of the claims.

I claim:

1. The method of close coiling a sheathed reinforcing wire in which the sheath is unbonded to the wire by means of a coiling machine having a plurality of rotating advancing rolls between which said sheathed wire is gripped and a plurality of rotatable forming rolls between which said sheathed wire passes and is formed into a coil of small diameter with the turns thereof pressing against each other, comprising rotating all of said rolls at the same peripheral speed as the speed at which the sheathed wire is advanced whereby there is no tendency for the sheath to be stripped-from the Wire.

2. The method according to claim 1 including the step of rotating the formed coil at the same rotative speed which it has as it leaves the forming rolls by means of a pair of rotating rolls upon and between which the coil is projected as it leaves the forming rolls.

References Cited in the file of this patent UNITED STATES PATENTS 58,156 Vose Sept. 18, 1866 250,528 Hayden Dec. 6, 1881 642,339 Krummel Jan. 30, 1900 1,023,099 Shuster Apr. 9, 1912 2,595,747 Andersen May 6, 1952 wile. 

